Possibly.. I'm sure the PC culture has taken hold, even in the military, in the 24 years since I served..
I know it wasn't a common term when I was in..
It's the current military slang equivalent for the old "Rebs", "Blue-bellies ", "Dons" (Spanish-American War), "Krauts", "Japs" or "Charlie".
It is more PC but, on the other hand, you can keep using it no matter what theater of operations you are in. :-)